A new metabolite of chlorpyrifos: isolation and identification

Lores, EM; Gw, Sovocool; Rl, Harless; Nk, Wilson; Rf, Moseman

doi:10.1021/jf60215a009

“…The EI mass spectrum for the oyster metabolite (Fig. 5) is identical to that previously observed for an O,O ‐diethyl‐ O ‐(dichloro‐methylthio‐2‐pyridyl)phosphorothioate compound found in a liver extract taken from a human suicide victim [28]. However, these researchers did not specifically identify the exact position of the ‐SCH 3 group on the pyridine ring system.…”

Section: Resultssupporting

confidence: 66%

The bioconcentration and metabolism of chlorpyrifos by the eastern oyster,Crassostrea virginica

Woodburn

¹

,

Hansen

²

,

Roth

³

et al. 2003

Enviro Toxic and Chemistry

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Eastern oysters (Crassostrea virginica) were exposed to [14C]chlorpyrifos (O,O-diethyl-O-[3,5,6-trichloro-2-pyridyl] phosphorothioate) at an average measured seawater concentration of 0.6 microg/L under flow-through conditions for 28 d. The compound O,O-diethyl-O-(3,5-dichloro-6-methylthio-2-pyridyl)phosphorothioate (DMP) was extracted and identified as the single metabolite observed, and this metabolite constituted the majority of the total [14C] activity in the oyster at all sampling times. Once oysters were exposed to clean water, both chlorpyrifos and DMP residues cleared rapidly from whole oysters, with elimination half-lives of <3 d. A simple two-compartment uptake/elimination model was adequate to describe total [14C] activity in whole oysters, edible tissue, and oyster liquor. The average bioconcentration factors (BCFs) for total [14C] activity in whole oysters, edible tissue, and oyster liquor were 565, 1,400, and 35 ml/g, respectively. The parent [14C]chlorpyrifos accumulated to a peak residue concentration of 135 microg/kg in whole oyster tissue, representing an empirical [14C]chlorpyrifos BCF value in the oyster of approximately 225 ml/ g; the BCF value for [14C]chlorpyrifos was lower than the BCF for total [14C] activity in whole oysters and edible tissue because of extensive metabolism to DMP and oyster elimination processes.

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“…The EI mass spectrum for the 1869 peak is presented in Figure 5 The EI mass spectrum for the oyster metabolite (Fig. 5) is identical to that previously observed for an O,O-diethyl-O-(dichloro-methylthio-2-pyridyl)phosphorothioate compound found in a liver extract taken from a human suicide victim [28]. However, these researchers did not specifically identify the exact position of the -SCH 3 group on the pyridine ring system.…”

Section: Metabolite Identificationsupporting

confidence: 57%

“…In the CI and EI metabolite mass spectra (Figs. 2 and 5), the isotopic abundances in the Mϩ2/Mϩ4 ion clusters are greater than that noted in the mass spectrum reported previously [28] and greater than anticipated, given the presence of a single sulfur atom (S) and two chlorine atoms. The expected isotopic abundances for a molecular ion or fragment with one S and two Cl atoms would be Mϩ (100%), Mϩ2 (70%), and Mϩ4 (11%) [29].…”

Section: Metabolite Identificationmentioning

confidence: 54%

“…The GC/MS data, the comparison to a synthesized metabolite standard under varying GC column conditions, and previous research [7,28] collectively indicate that the chlorpyrifos metabolite in the eastern oyster is DMP, with the methylthio at the 6-position (O,O-diethyl-O-[3,5-dichloro-6-methylthio-2-pyridyl]phosphorothioate). This transformation may occur in the oyster via the mercapturic acid pathway [31].…”

Section: Chlorpyrifos/oyster Metabolite: Summarymentioning

confidence: 61%

See 1 more Smart Citation

The Bioconcentration and Metabolism of Chlorpyrifos by the Eastern Oyster, Crassostrea Virginica

Woodburn¹,

Hansen²,

Roth³

et al. 2003

Environ Toxicol Chem

View full text Add to dashboard Cite

Eastern oysters (Crassostrea virginica) were exposed to [14C]chlorpyrifos (O,O-diethyl-O-[3,5,6-trichloro-2-pyridyl] phosphorothioate) at an average measured seawater concentration of 0.6 microg/L under flow-through conditions for 28 d. The compound O,O-diethyl-O-(3,5-dichloro-6-methylthio-2-pyridyl)phosphorothioate (DMP) was extracted and identified as the single metabolite observed, and this metabolite constituted the majority of the total [14C] activity in the oyster at all sampling times. Once oysters were exposed to clean water, both chlorpyrifos and DMP residues cleared rapidly from whole oysters, with elimination half-lives of <3 d. A simple two-compartment uptake/elimination model was adequate to describe total [14C] activity in whole oysters, edible tissue, and oyster liquor. The average bioconcentration factors (BCFs) for total [14C] activity in whole oysters, edible tissue, and oyster liquor were 565, 1,400, and 35 ml/g, respectively. The parent [14C]chlorpyrifos accumulated to a peak residue concentration of 135 microg/kg in whole oyster tissue, representing an empirical [14C]chlorpyrifos BCF value in the oyster of approximately 225 ml/ g; the BCF value for [14C]chlorpyrifos was lower than the BCF for total [14C] activity in whole oysters and edible tissue because of extensive metabolism to DMP and oyster elimination processes.

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“…Lores et al [77] studied metabolism of chlorpyrifos (O,O-diethyl O-3,5,6-trichloro-2-pyridyl phosphorothioate) in a lethal poisoning case. In course of the analysis they found a previously unreported hepatic metabolite of chlorpyrifos.…”

Section: Biomonitoring Of Human Exposurementioning

confidence: 99%